Installing A Blower System On a Corvette - Force-Feeding A C6

THERE'S AN UNDENIABLE allure to a supercharger. The debate over whether to go normally aspirated or forced induction in building power is a worthy one, but the academic reasons often fall to the simple fact that a blower is cool.

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Blowers look cool, and they certainly sound cool, and with the benefits of modern tuning-and the fact that modern Corvettes have never been better equipped to handle them-they're relatively efficient tools for making big horsepower in an otherwise stock vehicle.

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We've seen plenty of Roots-type blower systems on C5 and C6 Corvettes, most of them versions of MagnaCharger kits, but comparatively few centrifugal blowers. So when we had the opportunity to follow the installation of a Vortech-based, intercooled system from Oxnard, California's A&A Corvette, we loaded up our camera gear and camped out at Detroit-area tuning shop Stenod Performance for the wrench-turning session.

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"We were impressed with the kit," says Stenod's Joe Borschke. "From our experience installing and tuning it, it seems like a good value for our customers."

Although Vortech offers a specific, intercooled kit for the C6, A&A's system is priced approximately $1,800 lower. Differences between the two include things like fuel injectors and A&A's inclusion of a Kenne Bell Boost-A-Pump for the fuel system, but the biggest differentiator is tuning software. Vortech's C6 kit includes a plug-in programmer, while the A&A kit does not.

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"We don't believe in a pre-programmed tune," says A&A's Steve Padfield. "Each project is unique, so we believe it's best to have a custom tune performed at the time of installation."

Of course, that presupposes a qualified tuner is available in a customer's area. But assuming one is, it's definitely the method that ensures optimal performance. In the case of our project, additional engine modifications necessitated a custom tune that would have rendered a pre-programmed calibration unusable anyway.

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The test vehicle for this story was an '05 automatic with a mere 4,000 miles on the odometer. Like all '05 models, it features a 6.0L LS2 rated at 400 hp and 400 lb-ft of torque.

As with any intercooled system for a late-model Corvette, the installation involved removing the front bumper cover to provide room for the heat exchanger and related plumbing. Generally speaking, the kit was well engineered and used first-class materials. Kevin Gluski, the installer at Stenod Performance, found some of the instructions in the downloadable assembly manual to be a bit vague, but the overall impression on the fit and finish was one of admirable quality.

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That's not to say the project wasn't without its difficulties. Regardless of whose kit is used, stuffing an intercooled supercharger system into the tight confines of a Corvette's nose isn't easy. Care must be taken to ensure adequate clearance for a variety of hoses, tubes, electrical lines, and more. There are a few other details worth mentioning:

Like all late-model, LS-engine vehicles, the precaution of "pinning" the crankshaft is necessary, because the balancer is press-fitted to the crank hub. Pinning the crank involves drilling a hole or two between the balancer and crank, and inserting a dowel-type pin to provide a simple lock between them. This prevents unwanted slippage that could occur under the greater load imposed by the supercharger.

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Pinning the crankshaft requires the removal of the steering rack, which includes holding the steering wheel in place to ensure it aligns perfectly when the rack is re-installed. Otherwise, driveability will suffer, and the rack will likely need to be removed again to correct the problem. Reinstallation of the steering rack automatically means a trip to the alignment shop, too.

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Installing A Blower System On a Corvette - Force-Feeding A C6

The A&A Corvette supercharger kit for C6s includes a Vortech V-2 SQ compressor, an adjustable bypass valve, and A&A's unique bracket/pulley design, which offers excellent belt wrap (the amount of the blower pulley that is in contact with the drive belt) to all but eliminate the chance for slippage. Not seen in this photo is the large heat exchanger for the air-to-air charge cooling system.

The kit comes with a 3.8-inch supercharger drive pulley that enables about 10 pounds of boost. That's great for street-driven vehicles that will be tuned for pump gas. The company also offers smaller- and larger-diameter pulleys that alter the maximum boost; smaller pulleys increase boost, but sometimes at the cost of pump-gas driveability.

To facilitate the task of "pinning the crankshaft," the steering rack must also be removed. A&A Corvette also recommends removing the factory power-steering cooler in order to make room for the supercharger kit's plumbing. See the main text for more information on the pinning process.

In order to mount the intercooler and its related plumbing, as well as other components of the supercharger kit, the Corvette's front fascia must be removed. It involves carefully pulling out a number of delicate plastic push pins, as well as the removal of the front wheels.

There are two major things to note in this photo. First, at the 5 o'clock position on the crankshaft hub, the pin to lock together the crank and balancer/pulley is installed. Second, at the bottom right of the balancer/pulley, threaded into a drilled-and-tapped hole in the front of the oil pan, is the required oil-return port that links to the supercharger head unit.

When drilling and tapping the oil pan, white lithium grease should be used on the end of the bit to hold shards released during the drilling process. Keeping this debris out of the oil pan is vitally important. Some installers even drill the initial hole in the pan prior to draining the oil, allowing material to flow out with the old oil.

With the oil pan drilled and tapped, the oil-return line is connected to it and held out of the way until the supercharger itself is mounted to the engine.

Next, the rear portion of the supercharger bracket is installed in place of the factory belt tensioner. That's fine, because the A&A kit includes its own tensioner to be mounted on the bracket.

With the front part of the bracket attached to the supercharger head unit, the assembly is mated with the rear bracket. Trimming a bit of material from the factory water pump is necessary to ensure adequate clearance for the water pump.

When the supercharger is securely in place, the oil feed and return lines are installed. Shown here is the return line being installed. Not shown is the feed line that runs from a port in the cylinder block to the head unit. Proper attachment of both with Teflon tape on the fittings' threads is imperative to prevent leaks. Because the Vortech blower uses engine oil circulated through it, its lubrication is refreshed every time the engine oil is changed.

Some trimming of factory components was necessary in our case in order to mount the intake and discharge plumbing for the blower and intercooler. It included trimming the tabs at the top of the radiator. The aluminum material is easy to cut-almost too easy, so care must be taken to be precise with a cutter and/or grinder.

Another component to be trimmed is the passenger-side lower apron, near the factory brake cooling duct. A larger hole must be cut into it to provide routing room for plumbing from the blower to the heat exchanger.

Next, the large heat exchanger for the air-to-air-style intercooler is hoisted into place in front of the radiator. The air-to-air design speeds the kit's installation, as it doesn't require a separate cooling circuit that goes with the typical liquid-to-air intercooler design.

Here, a 90-degree silicone hose is shown feeding into the side of the heat exchanger. It's the discharged routing from the supercharger, which blows through the intercooler to reduce air temperatures and provide a more powerful, denser air charge at the engine. The denser charge also minimizes the chance for detonation in the Vette's relatively high-compression LS2. Note, too, the location of the bypass valve, which bleeds off excess boost when the throttle closes.

After all the intake and discharge hoses are plumbed under the hood, the rest of the engine work involves adding new, colder-range NGK TR-6 spark plugs and replacing the fuel injectors with the 60-lb/hr units that come with the blower kit. An engine with higher-capacity fuel injectors shouldn't be started until the ECM has been updated to reflect their presence, or big problems can occur.

Rather than replacing the factory in-tank fuel pump, the A&A Corvette kit comes with a Kenne Bell Boost-A-Pump system that increases the voltage to the factory pump and effectively "supercharges" its output. It mounts in the driver-side rear fenderwell. The inner fender liner is removed and re-installed over the system, for a hidden, well-protected installation.

Here's the completed installation of the supercharger kit. The close-out plate, with its OEM-looking black finish, looks great under the hood and is wholly appropriate for the premium feel of the Corvette. Stuffing all of the kit's plumbing into the nose of the Corvette wasn't exactly a cakewalk, but no major problems developed, and the general fit and finish of were excellent.

A custom calibration for the engine controller was performed by Stenod Performance upon the completion of the kit's installation. Stenod's techs tuned it not only for the supercharger, but for the additional engine modifications as well. These included L92 heads, a "blower" camshaft, an LS3 intake manifold, headers, and more. Then, it was onto Stenod's Mustang dyno to evaluate the shop's many hours of labor.

On the rollers, the supercharged LS2 delivered a stunning 508 hp at the rear wheels and 439 lb-ft of torque. And remember, this was through an automatic transmission and on a conservative-reading Mustang dyno. Peak numbers aside, that's a whopping 170hp/110-lb-ft jump over the baseline 338hp/329-lb-ft numbers. Talk about bang for the buck!

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